1. Field of the Invention
The present invention relates to an ultrasonic sensor assembly, which is installed to an installation object, such as a bumper of a vehicle, to sense presence of an obstacle.
2. Description of Related Art
A structure for installing an ultrasonic sensor apparatus, which senses presence of an obstacle, to a bumper of a vehicle is recited in Japanese Unexamined Patent Publication Number 2001-527480 (corresponding to U.S. Pat. No. 6,318,774).
In Japanese Unexamined Patent Publication Number 2001-527480, a through hole is formed through the bumper, and a holding member is secured to an opening edge of the through hole on an inner surface side of the bumper by, for example, welding. The holding member is formed into a tubular body, which receives the ultrasonic sensor apparatus (module) to form a sensor assembly. Furthermore, in order to limit sliding movement of the ultrasonic sensor apparatus in an axial direction of a sensing axis, engaging portions (projections), which project toward the holding member, are formed in the ultrasonic sensor apparatus, and engaging portions (grooves), which engage the engaging portions, respectively, of the ultrasonic sensor apparatus, are formed in the holding member. The engaging portions of the ultrasonic sensor apparatus and the engaging portions of the holding member form clip devices. Thus, the ultrasonic sensor apparatus is secured to the bumper through the holding member.
In the structure of Japanese Unexamined Patent Publication Number 2001-527480, the holding member, which includes the engaging portions, is resiliently deformably formed. Thus, the engagement between the engaging portions of ultrasonic sensor apparatus and the engaging portions of the holding member can be released by lifting the holding member, and thereby the ultrasonic sensor apparatus can be removed from the holding member.
However, in order to secure the ultrasonic sensor apparatus, the multiple clip devices (the multiple engaging portions of the ultrasonic sensor apparatus and the multiple engaging portions of the holding member) are formed. Thus, at the time of removing the ultrasonic sensor apparatus from the holding member, the multiple parts of the holding member, in which the engaging portions are provided, need to be lifted at once. Furthermore, since the holding member is formed into the tubular body, the multiple parts of the holding member, in which the engaging portions are provided, cannot be easily lifted. That is, the removal of the ultrasonic sensor apparatus cannot be performed smoothly. For example, at the time of manually removing the ultrasonic sensor apparatus from the holding member, it is difficult to remove the ultrasonic sensor apparatus by a single hand of an operator.